全文获取类型
收费全文 | 2914篇 |
免费 | 267篇 |
国内免费 | 138篇 |
专业分类
3319篇 |
出版年
2023年 | 27篇 |
2022年 | 71篇 |
2021年 | 83篇 |
2020年 | 68篇 |
2019年 | 76篇 |
2018年 | 101篇 |
2017年 | 81篇 |
2016年 | 104篇 |
2015年 | 110篇 |
2014年 | 123篇 |
2013年 | 164篇 |
2012年 | 180篇 |
2011年 | 194篇 |
2010年 | 136篇 |
2009年 | 105篇 |
2008年 | 146篇 |
2007年 | 129篇 |
2006年 | 120篇 |
2005年 | 98篇 |
2004年 | 88篇 |
2003年 | 79篇 |
2002年 | 92篇 |
2001年 | 63篇 |
2000年 | 61篇 |
1999年 | 51篇 |
1998年 | 31篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1992年 | 46篇 |
1991年 | 43篇 |
1990年 | 39篇 |
1989年 | 33篇 |
1988年 | 28篇 |
1987年 | 34篇 |
1986年 | 32篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 24篇 |
1982年 | 20篇 |
1981年 | 33篇 |
1980年 | 25篇 |
1979年 | 20篇 |
1978年 | 34篇 |
1977年 | 22篇 |
1976年 | 18篇 |
1975年 | 18篇 |
1974年 | 13篇 |
1973年 | 19篇 |
1969年 | 14篇 |
1968年 | 13篇 |
排序方式: 共有3319条查询结果,搜索用时 0 毫秒
61.
The objective of this study was to determine the prevalence, mutual associations, clinical manifestations, and diagnoses associated
with serum autoantibodies, as detected using recently available immunoassays, in patients with autoimmune myositis (AIM).
Sera and clinical data were collected from 100 patients with AIM followed longitudinally. Sera were screened cross-sectionally
for 21 autoantibodies by multiplex addressable laser bead immunoassay, line blot immunoassay, immunoprecipitation of in vitro translated recombinant protein, protein A assisted immunoprecipitation, and enzyme-linked immunosorbent assay. Diagnoses
were determined using the Bohan and Peter classification as well as recently proposed classifications. Relationships between
autoantibodies and clinical manifestations were analyzed by multiple logistic regression. One or more autoantibodies encompassing
19 specificities were present in 80% of the patients. The most common autoantibodies were anti-Ro52 (30% of patients), anti-Ku
(23%), anti-synthetases (22%), anti-U1RNP (15%), and anti-fibrillarin (14%). In the presence of autoantibodies to Ku, synthetases,
U1RNP, fibrillarin, PM-Scl, or scleroderma autoantigens, at least one more autoantibody was detected in the majority of sera
and at least two more autoantibodies in over one-third of sera. The largest number of concurrent autoantibodies was six autoantibodies.
Overall, 44 distinct combinations of autoantibodies were counted. Most autoantibodies were unrestricted to any AIM diagnostic
category. Distinct clinical syndromes and therapeutic responses were associated with anti-Jo-1, anti-fibrillarin, anti-U1RNP,
anti-Ro, anti-Ro52, and autoantibodies to scleroderma autoantigens. We conclude that a significant proportion of AIM patients
are characterized by complex associations of autoantibodies. Certain myositis autoantibodies are markers for distinct overlap
syndromes and predict therapeutic outcomes. The ultimate clinical features, disease course, and response to therapy in a given
AIM patient may be linked to the particular set of associated autoantibodies. These results provide a rationale for patient
profiling and its application to therapeutics, because it cannot be assumed that the B-cell response is the same even in the
majority of patients in a given diagnostic category. 相似文献
62.
Thachamvally Riyesh Vinayagamurthy Balamurugan Arnab Sen Veerakyathappa Bhanuprakash Gnanavel Venkatesan Vinita Yadav Raj Kumar Singh 《中国病毒学》2011,26(5):324-337
In this study, thermo-adapted (Ta) PPR vaccines were assessed for their stability at 25, 37, 40, 42 and 45°C in lyophilized
form using two extrinsic stabilizers {lactalbumin hydrolysate-sucrose (LS) and stabilizer E} and in reconstituted form with
the diluents (1 mol/L MgSO4 or 0.85% NaCl). The lyophilized vaccines showed an expiry period of 24–26 days at 25°C, 7–8 days at 37°C and 3–4 days at
40°C. LS stabilizer was superior at 42°C with a shelf-life of 44 h, whereas in stabilizer E, a 40 h shelf-life with a comparable
half-life was observed. At 45°C, the half-life in stabilizer E was better than LS and lasted for 1 day. Furthermore, the reconstituted
vaccine maintained the titre for 48 h both at 4°C and 25°C and for 24–30 h at 37°C. As both the stabilizers performed equally
well with regard to shelf-life and half-life, the present study suggests LS as stabilizer as a choice for lyophilization with
0.85% NaCl diluent, because it has better performance at higher temperature. These Ta vaccines can be used as alternatives
to existing vaccines for the control of the disease in tropical countries as they are effective in avoiding vaccination failure
due to the breakdown in cold-chain maintenance, as this vaccine is considerably more stable at ambient temperatures. 相似文献
63.
Fang M Zhang L Li J Wang C Chung CH Wai SM Yew DT 《Cellular and molecular neurobiology》2005,25(6):1043-1050
Summary The aim of this study was to evaluate the postnatal development of the cerebella of the pig and to compare this with the activation
of the fMRI. The cells in the cerebella were studied by silver technique and the activation of the fMRI in the cerebella was
initiated by flexion and extension of the hind paw. Our results showed an increase of the branching of the cells of the cerebellar
cortex postnatally, coordinated with registration of fMRI active sites in the cerebella at 6-month postnatal. We concluded
that the full maturation of the cerebella was around 6-month postnatal in the pig. 相似文献
64.
The purpose of this study was to achieve a better therapeutic efficacy and patient compliance in the treatment for vaginitis. Clotrimazole (1%) has been formulated in a vaginal gel using the thermosensitive polymer Pluronic F127 (20%) together with mucoadhesive polymers such as Carbopol 934 and hydroxypropylmethylcellulose (0.2% for both). To increase its aqueous solubility, clotrimazole was incorporated as its inclusion complex with 1:1 molar ratio with beta-cyclodextrin. The inclusion complex was thoroughly characterized using various techniques, including 1H NMR spectroscopy, FT IR spectrophotometry, differential scanning calorimetry, scanning electron microscopy, phase solubility studies, and determination of stability constant (k(1:1)). The gelation temperature and rheological behavior of different formulations at varying temperatures were measured. In vitro release profiles of the gels were determined in pH 5.5 citrate buffer. It was observed that complexation with cyclodextrin slowed down the release of clotrimazole considerably. Carbopol 934, on the other hand, was found to interact with beta-cyclodextrin, inducing precipitation. As far as rheological properties are concerned, thermosensitive in situ gelling was obtained with formulations containing drug:cyclodextrin complex rather than with free drug. Thus, the optimum formulation for a controlled-release thermosensitive and mucoadhesive vaginal gel was determined to be clotrimazole:beta-cyclodextrin 1% with 0.2% hydroxypropylmethylcellulose in Pluronic F127 gel (20%) providing continuous and prolonged release of active material above MIC values. 相似文献
65.
66.
卡巴胆碱对缺血再灌注大鼠小肠组织髓过氧化物酶的影响 总被引:5,自引:0,他引:5
研究拟胆碱药卡巴胆碱对大鼠缺血再灌注损伤小肠组织髓过氧化物酶 (MPO)和丙二醛 (MDA)的影响及其与肠损伤相关指标变化的规律。Wistar大鼠被随机分为预防、治疗和对照三组。活杀后取小肠组织测MPO、MDA和肿瘤坏死因子 (TNF-α)含量。结果显示 ,治疗组及预防组MPO活性、MDA和TNF -α含量均明显低于对照组 ,治疗组与预防组之间差异不明显。提示卡巴胆碱可抑制致炎因子TNF -α的释放 ,减少中性粒细胞在肠组织的聚集 ,从而使小肠MPO活性降低 相似文献
67.
DNA samples extracted from the root nodules of Alnus nepalensis, collected from 10 different locations of Darjeeling hills, were used to assess the genetic diversity of Frankia. The DNA samples from the nodules of naturally growing plants were used as templates in PCR, targeting different genomic regions of Frankia, namely distal, middle and proximal parts of 16S rRNA gene and nifH-D IGS region with locus specific primers. The PCR products were digested with a number of frequent (4-base) cutter restriction endonucleases. Bands were scored as present (1) or absent (0) and the clustering was done using NTSYSpc. Distinct polymorphism was found among the nodules collected from different parts of the region and those of same geographic area. These results demonstrate that genetic diversity is indeed present among the naturally occurring Frankia of Darjeeling, India. 相似文献
68.
Suman Kanungo Bandana Sen Thandavarayan Ramamurthy Dipika Sur Byomkesh Manna Gururaja P. Pazhani Goutam Chowdhury Puja Jhunjhunwala Ranjan K. Nandy Hemanta Koley Mihir Kumar Bhattacharya Sanjay Gupta Gaurav Goel Bindu Dey Thungapathra M G. Balakrish Nair Amit Ghosh Dilip Mahalanabis 《PloS one》2014,9(7)
Background
A live oral cholera vaccine VA 1.4 developed from a non-toxigenic Vibrio cholerae O1 El Tor strain using ctxB gene insertion was further developed into a clinical product following cGMP and was evaluated in a double-blind randomized placebo controlled parallel group two arm trial with allocation ratio of 1∶1 for safety and immunogenicity in men and women aged 18–60 years from Kolkata, India.Method
A lyophilized dose of 1.9×109 CFU (n = 44) or a placebo (n = 43) reconstituted with a diluent was administered within 5 minutes of drinking 100 ml of a buffer solution made of sodium bicarbonate and ascorbic acid and a second dose on day 14.Result
The vaccine did not elicit any diarrhea related adverse events. Other adverse events were rare, mild and similar in two groups. One subject in the vaccine group excreted the vaccine strain on the second day after first dose. The proportion of participants who seroconverted (i.e. had 4-folds or higher rise in reciprocal titre) in the vaccine group were 65.9% (95% CI: 50.1%–79.5%) at both 7 days (i.e. after 1st dose) and 21 days (i.e. after 2nd dose). None of the placebo recipients seroconverted. Anti-cholera toxin antibody was detected in very few recipients of the vaccine.Conclusion
This study demonstrates that VA 1.4 at a single dose of 1.9×109 is safe and immunogenic in adults from a cholera endemic region. No additional benefit after two doses was seen.Trial Registration
Clinical Trials Registry-India, National Institute of Medical Statistics (Indian Council of Medical Research) CTRI/2012/04/002582 相似文献69.
70.
Basidiomycetous fungus Flammulina velutipes R15 strain had two linear plasmids in its mitochondria designated pFV1 and pFV2. They were double-stranded DNAs, whose sizes were 8.3 and 8.9 kb, respectively. Sequencing analysis of 7364 bases of the pFV1 and 6861 bases of the pFV2 revealed that the both plasmids had one set of two open reading frames (ORFs) each of that encoded putative DNA and RNA polymerases similar to those of mitochondrial plasmids in other filamentous fungi. In phylogenetic analysis of deduced amino acid sequences of the ORFs and counterparts of other filamentous fungi, the pFV2 was expectedly clustered with plasmids of basidiomycetous fungi. whereas the pFV1 with kalilo plasmid of ascomycetous fungus Neurospora intermedia. 相似文献